Conventional methods for recovering platinum group elements from spent vehicle exhaust gas purification catalysts (ceramic carrier catalysts, metal carrier catalysts and the like from exhaust gas converters, which will be collectively called “discarded vehicle-use catalysts”) include, for example, the method of extracting platinum group elements from a solution obtained by adding an oxidizing agent to aqua regia or the method of, conversely, dissolving the carrier in sulfuric acid or the like and separating the undissolved platinum group elements. However, such wet methods have been found to be impractical owing to inferior platinum group element extraction rate and to recovery and cost problems caused by, for instance, the use of large amounts of acid for dissolving the carrier.
In contrast, the methods taught by applicant's JP-H4-317423A and JP-2000-248322A conduct distinctive dry processing in which platinum group elements are transferred into molten metal (molten copper metal) by melting a discarded vehicle-use catalyst or other platinum group element-containing substance together with a copper-containing material (copper oxide and/or metallic copper) in a furnace. When these methods are combined with an enrichment process in which the molten metal containing the platinum group elements obtained in this manner is oxidized and then separated into a molten oxide phase and a molten metal phase of enhanced platinum group element concentration, the platinum group elements can be recovered at a high recovery rate and low cost, thus offering an economical resource recovery method with advantages not possessed by wet methods.